Category Archives: General

When evaluating a clinical trial, readers often jump to the P value of the primary endpoint to determine whether the results of a trial are “statistically significant” or not. Although the P value is truly a continuous variable, the scientific community has been conditioned to disregard all results with P values ≥ 0.05, but to fully endorse any trials with a “statistically significant” P value less than 0.05.

Putting the debate and controversy about P values aside for the moment, as a reader, would you be less impressed with a study that changed from being statistically significant to insignificant if one single patient changed from not having the primary endpoint to having the primary endpoint? Especially in an era with a blind reliance on P values, the knowledge of the “fragility” or “robustness” of a study’s P value is another useful data point for readers to critically understand and analyze the results of a clinical trial.

The Concept of the “Fragility Index” for Clinical Trials

In the United States, vitamin D supplementation is primarily available as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Although these two have historically been considered interchangeable and equipotent, the current body of literature strongly supports the preference of Vitamin D3 (cholecalciferol) over D2 (ergocalciferol).

Vitamin D2 versus Vitamin D3

Vitamin D3 (cholecalciferol) is produced by the human body in response to sunlight and is also available through dietary sources, such as fish. In contrast, vitamin D2 (ergocalciferol) is not produced in the human body, but is created by exposing certain plant-derived materials to ultraviolet light.

ClinCalc.com has been a bit quiet over the past year. Our Twitter account has been mute, email updates rare, and website updates sparse.

Why the radio silence?

We’ve been diligently working on an exciting new product for the past year. Quite literally, HUNDREDS of hours have been poured into the conception, creation, and implementation of this amazing new product. Given this massive undertaking, we’ve kept website and mobile app updates to a minimum in order to expedite our production schedule. Continue reading →